Serosal overturning assisted endoscopic full‐thickness mucosal resection of extraneous giant mass at the esophagogastric junction

Key Clinical Message Serosal overturning assisted endoscopic full‐thickness mucosal resection was performed on the extraneous giant masses at the esophagogastric junction without complications. Abstract It is difficult to perform endoscopic resection of masses at the gastroesophageal junction (GEJ). In particular, the extraneous giant masses surrounding the extraneous giant masses is infrequent. As one of the technologies of endoscopic resection, endoscopic full‐thickness resection (EFTR) is generally applicable to the submucosal tumor of stomach, duodenum and colorectal that originate from the musculus propria and protrude to subserous or partial growth outside the luminal layer. Successful endoscopic repair of perforation is crucial in avoiding the need for surgical repair and preventing postoperative peritonitis, making it a key aspect of EFTR treatment. We report a 56‐year‐old woman who was admitted to our department complaining of 5‐year history of masses of esophagogastric junction and 2‐month history of feeling of gastric distension. Gastroscopy showed a 4 cm submucosal mass near the fundus of the stomach from the cardia. Computed tomography scan revealed submucosal lesions in esophagogastric junction, which was exogenous. We successfully performed Serosal overturning assisted endoscopic full‐thickness mucosal resection on the extraneous giant masses at the esophagogastric junction without complications. The clinical symptoms were significantly improved within postoperative 1 month. There was no recurrence 8 months after the operation. Serosal overturning assisted EFTR is possibly an effective and minimally invasive method of extraneous giant masses at the esophagogastric junction.

extraneous giant masses is infrequent.As one of the technologies of endoscopic resection, endoscopic full-thickness resection (EFTR) is generally applicable to the submucosal tumor of stomach, duodenum and colorectal that originate from the musculus propria and protrude to subserous or partial growth outside the luminal layer.Successful endoscopic repair of perforation is crucial in avoiding the need for surgical repair and preventing postoperative peritonitis, making it a key aspect of EFTR treatment.We report a 56-year-old woman who was admitted to our department complaining of 5-year history of masses of esophagogastric junction and 2-month history of feeling of gastric distension.Gastroscopy showed a 4 cm submucosal mass near the fundus of the stomach from the cardia.
Computed tomography scan revealed submucosal lesions in esophagogastric junction, which was exogenous.We successfully performed Serosal overturning assisted endoscopic full-thickness mucosal resection on the extraneous giant masses at the esophagogastric junction without complications.The clinical symptoms were significantly improved within postoperative 1 month.There was no recurrence 8 months after the operation.Serosal overturning assisted EFTR is possibly an effective and minimally invasive method of extraneous giant masses at the esophagogastric junction.

K E Y W O R D S
endoscopic full-thickness mucosal resection, Esophagogastric junction, extraneous giant mass, Serosal overturning

| INTRODUCTION
Due to the specific anatomical structure of the esophagogastric junction, it is regarded as one of the most difficult parts in endoscopy examination. 1 Stripping the mass at the esophagogastric junction requires more accurate and stable endoscopic operation.Furthermore, there is a high risk of an exogenous mass falling into the abdominal cavity.The larger the tumor, the longer and more difficult the operation of endoscopic resection, and the higher the risks of intraoperative perforation, postoperative infection and delayed bleeding. 2For submucosal tumor at the esophagogastric junction, endoscopic full-thickness resection (EFTR) can treat deeper lesions of the digestive tract and expand the scope of endoscopy treatment.We encountered a woman with a giant extraneous mass at the esophagogastric junction.The mass was successfully excised by EFTR assisted with serosal overturning, without postoperative complications.

| CASE HISTORY/ EXAMINATION
A 56-year-old woman admitted to the Department of Gastroenterology of The second affiliated hospital of Guangzhou University of Chinese Medicine.She had 5year history of mass at the esophagogastric junction and 2-month history of feeling of gastric distension.Five years ago, she was found to have a mass at the esophagogastric junction by endoscopy and contrast-enhanced thoracic computed tomography (CT) (Figure 1A and Figure 2A).However, she did not take any treatment because negligence without any symptom.Gastroscopy on admission showed a 4-cm submucosal mass near the fundus of the stomach from the cardia (Figure 1B).The surface was smooth and the contact was hard and immobile.As shown in Table 1, physical examination and laboratory findings were unremarkable.Contrast-enhanced whole abdomen CT scan revealed a submucosal lesion at the esophagogastric junction (Figure 2B), which was slight larger compared with the images 5 years ago (3.6 cm × 2.2 cm vs. 3.5 cm × 2.2 cm).There was a low-density fat gap with nonuniformity of image density and multiple nodular density shadow between pancreatic neck and the mass (Figure 2).Endoscopic ultrasonography (EUS) demonstrated that the mass was derived from the musculus propria and surrounded about half of the cavity, with irregular shape.About half of the lesions were located outside the cavity with inhomogeneous low-echo light group, and multiple patchy hyperecho were observed outside the cavity (Figure 1C).

| METHODS
After obtaining informed consent, EFTR combined with lower serosal overturning was carried out by aspiration lumpectomy.

| DISCUSSION
The gastroesophageal junction (GEJ), a 2-cm interface between the distal esophagus and the gastric fundus, predominantly features a muscularis propria layer.The majority of esophageal submucosal tumors originating in this region are benign; however, a minority exhibit malignant potential. 3Current clinical guidelines widely recommend early resection of muscularis propria tumors at the GEJ. 4 Laparoscopy can effectively treat tumors that grow into the abdominal cavity. 5However, it must remove part of the esophagus, resulting in the destruction of the inherent anatomy and functional structure of the GEJ. 6,7pen surgical procedures could cause more trauma to the body and a higher incidence of complications. 8,9][12] The current endoscopic treatments for propria tumors include endoscopic submucosal excavation (ESE), EFTR, and submucosal tunnel endoscopic resection (STER).ESE, an evolution of endoscopic submucosal dissection (ESD), is predominantly indicated for submucosal tumors with a diameter of 2 cm or greater. 13Studies have shown a high complete resection rate, exceeding 90%, for ESE in submucosal tumors, [14][15][16] with perforation being the most common complication. 16,17STER, built upon peroral endoscopic myotomy (POEM) technology, represents an extension of ESD techniques, particularly for esophageal and gastric submucosal tumors originating from the muscularis propria with diameters below 5 cm.][20] Independent risk factors for incomplete resection include irregular tumor morphology, deep muscularis propria origin, intraoperative air perfusion, and procedures lasting more than 60 min. 18EFTR is typically employed for submucosal tumors in the stomach, duodenum, and colorectal regions, originating from the muscularis propria.CT scans indicate tumors extending to the subserosal layer or partially protruding beyond the luminal surface.EUS reveals tight adherence to the serosal layer, making separation challenging, Moreover, EFTR is indicated for esophageal submucosal tumors with diameters exceeding 5 cm, where STER is not applicable.The reported complete resection rate for EFTR in these tumors ranges from 87.5% to 100%, with a low incidence of complications, including a few reported cases of abdominal infection postprocedure. 21,22he current case study documents an atypical esophagogastric junction mass.Both the CT scan and EUS findings revealed the tumor's extension beyond the serosal margin and partial infiltration into the submucosal layer, indicating its eligibility for EFTR.Hence, we opted for EFTR as the treatment modality.Success in EFTR is predicated on effectively managing perforation, preventing surgical intervention, and minimizing postoperative peritonitis, as highlighted in studies. 2,23At present, the metal clip stitching, aspiration-clipping suture, omental patch suture, and string suture are the main suture techniques for EFTR. 23The metal clip is the most basic suture tool in EFTR repair, applied to completely suture the wound from both sides to the center under endoscopic direct vision.Due to the limited span of the metal clip, multiple metal clips are used to close the perforation, also known as "aspiration-clipped suture." 24If the wound is too large, negative pressure can be applied to attract the omental momentum into the digestive tract cavity.Metal clips can then be used to clamp the omental patch and mucosa along the edge of the wound to close it, a procedure known as "omental patch suture."The string suture is performed under double forceps endoscopy.In one forceps passage, nylon rope is placed around the incisor edge of the gastric wall.In the other forceps passage, multiple metal clips are placed to close the mucosal tissue and secure the nylon rope at the incisor edge.Finally, the nylon rope is tightened to close the wound. 25n the present case, the metal clip stitching and aspiration-clipping suture were applied.Additionally, a new method named "serosal overturning" was used to assist with the suturing.When serosal protrusions are outside the lumen, they are abundant in blood vessels.It is challenging to deal with the exposed blood vessels of the serosa since the endoscope in the cavity cannot directly view the serous membrane outside the cavity at the perforation."Serosal overturning" involves fixing the serosa at the lower end of the perforation with a metal clip at one end, pulling the clip and serosa into the cavity with thread at the other end, and then solidifying and clamping the exposed blood vessels with metal clips (Figure 3).This method helps reduce bleeding during surgery and shorten the time for suturing the perforation.
In conclusion, we described an unusual presentation of an extraneous giant mass at the esophagogastric junction.In addition, a new method named "serosal overturning" was used to assist with suturing.The Serosal overturning assisted EFTR is possibly an effective and minimally invasive method of extraneous giant mass at the esophagogastric junction.

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I G U R E 1 Endoscopy.(A) An endoscopic view from 2016: Protruding mass with a smooth surface was observed in the esophagogastric junction.(B) An endoscopic view from 2021: Protruding mass with slightly hyperemic surface was observed in the esophagogastric junction.(C) Endoscopic ultrasonography from 2021: A mass was derived from the musculus propria and surrounded about half of the cavity, with irregular shape.

F I G U R E 2
Conventional and enhanced computed tomography (CT) images.A submucosal mass protruding into the abdominal cavity was seen in esophagogastric junction.(A) the CT image 5 years ago; (B) the CT image on admission.